/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.attribute.preverification;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.attribute.preverification.visitor.*;

/**
 * This StackMapFrame represents a "same locals 1 stack item frame" or a "same locals 1 stack item frame extended".
 *
 * @author Eric Lafortune
 */
public class SameOneFrame extends StackMapFrame {
    public VerificationType stackItem;

    /**
     * Creates an uninitialized SameOneFrame.
     */
    public SameOneFrame() {}

    /**
     * Creates a SameOneFrame with the given tag.
     */
    public SameOneFrame(int tag) {
        u2offsetDelta = tag - SAME_ONE_FRAME;
    }

    /**
     * Creates a SameOneFrame with the given stack verification type.
     */
    public SameOneFrame(VerificationType stackItem) {
        this.stackItem = stackItem;
    }

    /**
     * Applies the given verification type visitor to the stack item.
     */
    public void stackItemAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        VerificationTypeVisitor verificationTypeVisitor) {
        stackItem.accept(clazz, method, codeAttribute, offset, verificationTypeVisitor);
    }

    // Implementations for StackMapFrame.

    public int getTag() {
        return u2offsetDelta < 64 ? SAME_ONE_FRAME + u2offsetDelta : SAME_ONE_FRAME_EXTENDED;
    }

    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        StackMapFrameVisitor stackMapFrameVisitor) {
        stackMapFrameVisitor.visitSameOneFrame(clazz, method, codeAttribute, offset, this);
    }

    // Implementations for Object.

    public boolean equals(Object object) {
        if (!super.equals(object)) {
            return false;
        }

        SameOneFrame other = (SameOneFrame)object;

        return this.u2offsetDelta == other.u2offsetDelta && this.stackItem.equals(other.stackItem);
    }

    public int hashCode() {
        return super.hashCode() ^ stackItem.hashCode();
    }

    public String toString() {
        return super.toString() + "Var: ..., Stack: [" + stackItem.toString() + "]";
    }
}
